Method and device for a stream vortex transformation

ABSTRACT

The invention relates to wind-power engineering and makes it possible to form a swirling vortex stream, to reduce a blade aerodynamic drag, to increase a stream kinetic energy and to reduce a converter power losses. The inventive method for a stream vortex transformation consists in guiding an input three-dimensional stream towards the internal concave blade surfaces ( 7 ) and in forming vortex cords thereon with the aid of vortex cord formers ( 8 ) which are arranged at an angle to the blade axis of rotation. A vortex converter comprises an axis and helical blades connected thereto with the aid of steppedly arranged holders and posts. The blade is a thin-shaped, has an aerodynamic profile shape and consists of at least two layers connected to each other. The vortex cord formers ( 8 ) are arranged on the internal concave surface ( 7 ) of a collecting layer across the blade and the cross section thereof is embodied in a saw-like form and has asymmetrical sides, the smallest of which is caved-in in an arc-like manner.

The invention pertains to wind power, especially the rotors of wind turbines for transformation of wind energy into mechanical and electrical energy, and it can be used in designs of vortex apparatus for phase and component separation of mixtures; in hydraulic engineering, in designs of pumps, turbines, and hydraulic engineering structures; in designs of vortex separators and rectifiers of gas, gas/condensate, and dust/gas mixtures; in aviation and ship building in the designs of propeller screws and turbines; in designs of vortex carburetors and ejectors; in devices for the modeling of vortex processes and measurement devices.

There is a known method of vortex transformation of a stream, involving the directing of an incoming stream onto the internal surface of a stationary device and swirling the stream by means of helical guide [1].

However, the known method has an inadequate degree of swirling of the stream and, accordingly, fewer possibilities for generating energy.

The problem of the invention is to increase the effectiveness of the vortex transformation of the stream, to increase the power and the reliability of the device.

The stated problem is solved in that there is proposed a method of vortex transformation of a stream, involving the directing of an incoming stream onto the internal concave surfaces of blades and the formation of vortices at these surfaces. This increases the kinetic energy of the incoming stream by the vortex cords which are formed by means of vortex cord formers arranged on the internal surface of the blades at an angle to the axis of rotation.

Each blade, being thin [2], will contain a minimum of two layers, joined together, and is fastened to the axis of rotation with an axial gap.

The blade's cross section profile is in the form of a complex curve, close to the shape of an effective aerodynamic profile, as described by the mathematical expression: L/D=2.5, where L is the length of the horizontal projection of the profile, and D is the diameter of the inscribed circle [3], with a natural shape correction depending on the elasticity of the composite material of the inner layer of the blade, produced by pretensioning of the elements of the inner layer of the blade at the points of fastening to the elements of the load-bearing structures. The profile ends in a fairing or flap, whose curvature increases toward the axis of rotation [4, 5].

The vortex cord formers are oriented in the direction of the incoming stream, they are made to taper toward the axis of rotation, and their edges are in the form of an asymptotically decreasing profile.

The cross section of each former is saw-shaped with asymmetrical sides, the smaller of which is a concave arc.

Upon detachment of the flow from the internal surface in the area of the axis of rotation, a joining of the vortex cords coming off occurs [14], while the drag of the medium decreases substantially [6], and the strongly swirled vortex stream formed by the joined vortices in the region of the axis of rotation is broken up by an oncoming axial current [7].

There is a known design of rotor for wind and water turbines with two hollow blades and an aerodynamic profile of parabolic or spiral shape, with an axial gap, and with no torsion about the axis [8].

The drawback of the known design is its low efficiency, as well as its inadequate strength.

A wind motor is known, which contains a vertical axis to which are joined at least two helical blades that are arc shaped in cross section. Each blade is assembled from horizontally arranged strips, the larger sides of which are placed overlapping, while the smaller sides are rigidly fastened to lateral profiles. The cross section of the blade can be semicircular [9].

The drawbacks of the known wind engine result from the limited possibilities for the construction and operation of large-power wind motors.

The semicircular cross section of the wind motor blade has a substantial coefficient of aerodynamic drag, which leads to a loss of power of the wind motor and an overloading of the joints and structures of the wind motor.

The problem solved by the proposed invention consists in increasing the efficiency and reliability of the stream vortex transformation device, for example, when using it in regions with relatively low yearly average wind speed values, and also during extreme wind loads.

The stated problem is solved by proposing a stream vortex transformer, containing an axis of rotation and one or more helical blades, which are made thin, arc shaped in cross section, and joined to the axis by means of holders and poles arranged in tiers.

The blades, holders and poles are pretensioned, forming an integrated stressed structure [10, 11], thereby achieving greater strength.

Each blade contains at least two layers joined together and fastened to the axis of rotation with an axial gap.

The blade's cross section profile is in the form of a complex curve, close to the shape of an effective aerodynamic profile, as described by the mathematical expression: L/D=2.5, where L is the length of the horizontal projection of the profile, and D is the diameter of the inscribed circle, with a natural shape correction depending on the elasticity of the material of the inner layer of the blade, produced by pretensioning of the elements of the inner layer of the blade at the points of fastening to the elements of the load-bearing structures, and the profile ends in a fairing or flap, whose curvature increases toward the axis of rotation.

Vortex cord formers are made on the internal concave surface of the composite layer in the cross section of the blade, and these are oriented in the direction of the incoming stream and taper toward the axis of rotation of the rotor.

The cross section of each of the formers is saw-shaped with asymmetrical sides, the smaller of which is a concave arc, and the edges of each former are in the form of an asymptotically decreasing profile.

The profile of the aerodynamic projection of the vortex transformer can be conical, narrow-cylindrical with a conical tip at one end or spindle-shaped according to the Phyllotaxis rule [12].

The axis of rotation can coincide with the direction of the incoming stream, or may not coincide with it.

The shape of each individual element of the compound layer can have a shape close to the shape of a trapezium.

The smaller concave arc-shaped side of the vortex cord former, which is the working side, is oriented to face the flow reflected from the internal surface of the blade, when the axis of rotation of the rotor is placed vertically.

The blade holders are arranged on the axis of rotation along a helical line with a variable angular displacement according to the Phyllotaxis rule.

Making the helical blade thin, prestressed, with a variable angle of pitch and a cross-sectional profile in the form of a complex curve, close to the shape described by the mathematical expression: L/D=2.5, with natural shape correction depending on the elasticity of the material of the inner layer of the blade, produced by the pretensioning of the elements of the inner layer of the blade at the points of fastening to the elements of the load-bearing structures of the blade, and terminating in a fairing or flap, whose curvature increases toward the axis of rotation, and also containing two layers, joined together, one of which (the outer) has a smooth surface, while the other is a compound layer, reduces the aerodynamic resistance of the blade and makes it possible to produce a strongly twisted vortex jet.

The presence on the surface of the compound layer of the blades of vortex cord formers, the cross section of each of which is saw-shaped with asymmetrical sides, with a smaller concave arc-shaped side, turned toward the flow reflected from the inner surface of the blade, is responsible for increasing the kinetic energy, while their being oriented in the direction of the incoming flow and their tapering toward the axis of rotation, with a merging of the vortex cords coming off the internal surface of the blade, creates conditions for the formation of a “wave resistance crisis”, which leads to a significant decrease in the power losses at the flow exit. The axial countercurrent in the region of the axis of rotation, breaking up the strongly swirled vortex flow, has been experimentally recorded, and it further lowers the power losses at the flow outlet [13].

Making the edges of each former in the shape of an asymptotically decreasing profile at the flow inlet reduces the aerodynamic resistance, and at the outlet in the flow detachment zone it lowers the level of acoustic oscillations.

The result of the invention consists of producing a strongly swirled vortex flow, lowering the aerodynamic drag of the blades, increasing the kinetic energy of the flow on the internal surface of the blades by means of a system of vortices formed by the vortex cord formers, decreasing losses upon the merging of vortex cords coming off from the internal surfaces of the blades, and disrupting the strongly swirled vortex current by the axial countercurrent, which has been experimentally recorded, which further decreases the power losses at the exit of the currents from the former. The structural elements of the flow transformer: holders, poles and blades, are prestressed, forming an integrated stresses structure, ensuring strength conditions under extreme loads.

The invention is explained by drawings, shown in FIGS. 1 to 17, which depict:

FIG. 1. Vortex stream transformer of conical shape with one helical blade when the axis of rotation is in a position not coinciding with the direction of the incoming flow, general view;

FIG. 2. Cross section of FIG. 1;

FIG. 3. View A of FIG. 1;

FIG. 4. Section B-B of FIG. 1;

FIG. 5. Aerodynamic profile of the blade;

FIG. 6. Conical profile of the aerodynamic projection of the vortex stream transformer when the axis of rotation is in a position not coinciding with the direction of the incoming flow;

FIG. 7. Narrow-cylindrical profile of the aerodynamic projection of the vortex stream transformer with a conical tip, when the axis of rotation is in a position not coinciding with the direction of the incoming flow;

FIG. 8. Spindle-shaped profile of the aerodynamic projection of the vortex stream transformer when the axis of rotation is in a position not coinciding with the direction of the incoming flow;

FIG. 9. Conical profile of the aerodynamic projection of the vortex stream transformer when the axis of rotation is in a position coinciding with the direction of the incoming flow;

FIG. 10. Narrow-cylindrical profile of the aerodynamic projection of the vortex stream transformer with a conical tip, when the axis of rotation is in a position coinciding with the direction of the incoming flow;

FIG. 11. Spindle-shaped profile of the aerodynamic projection of the vortex stream transformer when the axis of rotation is in a position coinciding with the direction of the incoming flow;

FIG. 12. Vortex stream transformer of conical shape with two helical blades when the axis of rotation is in a position not coinciding with the direction of the incoming flow;

FIG. 13. Cross section of FIG. 12;

FIG. 14. Vortex stream transformer of conical shape with three helical blades when the axis of rotation is in a position not coinciding with the direction of the incoming flow;

FIG. 15. Cross section of FIG. 14;

FIG. 16. Vortex stream transformer of conical shape with four helical blades when the axis of rotation is in a position not coinciding with the direction of the incoming flow;

FIG. 17. Cross section of FIG. 16;

The vortex stream transformer contains an axis 1 and one or more helical blades 2, which are thin, arc-shaped in cross section, and joined to the axis 1 by holders 3 arranged in tiers. The holders are fastened to the axis of rotation 1 along a helical line with variable angular displacement according to the Phyllotaxis rule. Poles 4 which fix the outer edges of the blades 2 are fastened coaxially to the holders 3.

The axis of rotation 1 may coincide with the direction of the incoming flow or it may not.

The blades 2, holders 3 and poles 4 are prestressed, forming an integrated stressed structure of the vortex stream transformer, ensuring conditions of strength under extreme loads.

The cross-sectional profile of the blade is in the shape of a complex curve, close to the shape of the effective aerodynamic profile described by the mathematical expression: L/D=2.5, where L is the length of the horizontal projection of the profile, and D is the diameter of the inscribed circle, with a natural shape correction at the points of fastening to the elements of the load-bearing structures, depending on the elasticity of the material of the inner layer of the blade, produced by the pretensioning of the elements of the inner layer of the blade at the points of fastening to the elements of the load-bearing structures of the blade. The profile ends in a fairing or flap 5, whose curvature increases toward the axis of rotation 1.

The blade 2 contains at least two layers, joined together, one of which (the outer 6) has a smooth outer convex surface, while the other is a compound layer 7, made from separate elements, the lateral edges of which are joined together. The shape of each individual element of the compound layer 7 of blade 2 is close to the shape of a trapezium. On the inner concave surface of the compound layer 7, vortex cord formers 8 are arranged crosswise to each blade, being oriented in the direction of the incoming flow and converging toward the axis of rotation 1. The cross section of each former 8 is saw shaped with asymmetrical sides 9 and 10; the smaller side 9, which is the working one, is a concave arc, while the edges of each former are in the form of an asymptotically decreasing profile.

When the axis of rotation 1 is positioned vertically, the smaller side 9 of the vortex cord former 8 is oriented upward, to encounter the incoming flow reflected from the inner surface of the blade 7.

The profile of the aerodynamic projection of the vortex stream transformer may have a conical shape, a narrow-cylindrical shape with conical tip at one end, and also a spindle shape according to the Phyllotaxis Rule.

The proposed method of vortex transformation of streams is realized as follows.

Flow Inlet

The incoming three-dimensional flow strikes the helical blade 2, situated with an axial gap relative to the axis of rotation 1, forming a vortex jet strongly twisted about the axis, with an experimentally recorded zone of back currents along the entire axis of rotation. In order to reduce the aerodynamic drag of the surface of the rotating solid body, the blade 2 is thin, with aerodynamic cross-sectional profile in the shape of a complex curve, close to the shape of the effective aerodynamic profile described by the mathematical expression: L/D=2.5, where L is the length of the horizontal projection of the curve, and D is the diameter of the inscribed circle, with a natural shape correction, and the profile of the blade ends in a fairing or flap 5, whose curvature increases toward the axis of rotation 1.

Flow transformations on the inner surfaces of the vortex stream transformer.

For an effective utilization of the energy of the incoming flow, vortex cord formers 8 are made on the inner concave surface 7 of the blade 2, converging at an acute angle toward the axis of rotation 1 of the vortex stream transformer. The kinetic energy of the medium will increase on the inner surface of the blades. The use of a fairing or flap, deflecting the streams on the inner surface of the blades, further increases the rotation of the blades.

The formation of vortex cords on the inner concave surface 7 of the blade 2 with a uniform direction of their twist, in keeping with the law of the combination of vortex cords, forms more powerful vortices when the vortices become detached, rotating relative to the center of the distance between them—for the case of two vortices. A “resistance crisis” effect is manifested: the resistance of the medium in the region of the flow detachment decreases significantly. In the region of flow detachment, the outer convex surface 6 has a fairing or flap 5, whose curvature increases toward the axis of rotation 1. A “smooth” detachment of the flow from the outer convex surface 6 of the blade 2 will occur, that is, the “Brillouin condition” is fulfilled, and the “smooth” detachment of the flow from the outer convex surface of the blades minimizes the effect on the conditions of formation of the “resistance crisis” during detachment of the vortices from the inner concave surface of the blades.

Exit of the Streams

The vortex flow twisted about the axis of rotation 1 is directed downward along the axis of rotation in the direction of the swirl of the blades.

Using the method of introducing paint into the exit region for swirled flow in the lower region of the axis of rotation 1, the inventors have experimentally established the presence of a vortex return flow along the entire axis of rotation 1, which makes it possible to classify the degree of swirl of the axial currents as being strongly twisted.

The description of the working of the vortex stream transformer is based on experimental data and theoretical foundations of the mechanisms of transformation of vortex structures, while the mechanism of collapse of a vortex as a perturbation is characterized by the arising of a point on the axis of the vortex, beyond which is situated the boundary region of return flow, adjacent to the axis of rotation [13]. The collapse of the vortex substantially reduces the losses at the exit of the streams.

BIBLIOGRAPHIC REFERENCES

1. Patent AT 117,749 B “Jet turbine”, Schauberger Viktor May 10, 1930.

2. G. Birkgof, “Hydrodynamics”, Inostrannaya literature [Foreign literature] press, Moscow, 1963, pp. 35-37.

3. Dr.-Eng. Wolf Heinrich Hucho, “Aerodynamics of the automobile”, Vogel Publ. Co., Wurzburg, p. 70.

4. G. Birkgof, “Hydrodynamics”, Inostrannaya literature [Foreign literature] press, Moscow, 1963, pp. 97-99.

5. Abstract “Airplane aerodynamics”, p. 18.

6. S. N. Postolovskii, K. P. Il'chei, “On aerodynamic resistance crisis”, Moscow, Energeticheskoye mashinostroyeniye, NIIE informenergomash, 1983, 1-83-01,

7. Leibovich Sidney, “The structure of vortex breakdown”. Annual Review of Fluid Mechanics 1978, vol 10, p. 221-246.

8. Patent F 27163 “Rotor for wind and water turbine”, Sigurd J. Savonius, Dec. 12, 1924. pp. 15-16.

9. Patent MD 1513F “Wind motor (variants)”, M. Polyakov, N. Polyakova, Jul. 31, 2000.

10. Donald E. Ingber, “The Architecture of Life”. Scientific American. January 1988, p. 48-57.

11. Robert William Burkhardt, Jr., “A Practical Guide to Tensegrity Design”, 2-nd edition, 2005.

12. John R. V., “Phyllotaxis: systemic investigation of the morphogenesis of plants” (translated from English), IKI Press, 2006.

13. S. Leibovich, “Vortex collapse”, p. 160, Vikhrevye dvizheniya zhidkosti [Vortex movement of a liquid], Mir Press, Moscow, 1979.

14. Prandtl L., Tit'ens O., “Hydromechanics and aeromechanics”, Gostekhtereoizdat, 1933. 

1. A method of vortex transformation of a stream, involving the directing of an incoming stream onto the internal surface of a stationary device and swirling the stream by means of helical guides, characterized in that the kinetic energy of the incoming stream is increased by vortex cords which are formed by means of vortex cord formers arranged at an angle to the axis of rotation of blades, each of which is thin and contains at least two layers, joined together, and fastened to the axis of rotation with an axial gap, while the blade's cross-sectional profile is in the form of a complex curve, close to the shape of an effective aerodynamic profile, as described by the mathematical expression: L/D=2.5, where L is the length of the horizontal projection of the profile, and D is the diameter of the inscribed circle [3], with a shape correction depending on the elasticity of the composite material of the inner layer of the blade, which is made to be thin, produced by pretensioning the elements of the inner layer of the blade at the points of fastening to the elements of the load-bearing structures; the profile ends in a fairing or flap, whose curvature increases toward the axis of rotation, and the vortex cord formers are oriented in the direction of the incoming stream; they are made to taper toward the axis of rotation, and their edges are in the form of an asymptotically decreasing profile; the cross section of each former is saw-shaped with asymmetrical sides, the smaller of which is a concave arc, and at the moment of detachment of the flow from the internal surface in the area of the axis of rotation, the drag of the medium decreases, and the strongly swirled vortex stream formed by the joined vortices in the region of the axis of rotation is broken up by an oncoming axial current.
 2. A stream vortex transformer, containing an axis of rotation and one or more helical blades, which are made arc shaped in cross section, and joined to the axis by means of holders and poles arranged in tiers, characterized in that the blades, holders and poles are pretensioned, forming an integrated stressed structure; each blade is thin and contains at least two layers joined together and fastened to the axis of rotation with an axial gap, while the blade's cross-sectional profile is in the form of a complex curve, close to the shape of an effective aerodynamic profile, as described by the mathematical expression: L/D=2.5, where L is the length of the horizontal projection of the profile, and D is the diameter of the inscribed circle, with a shape correction depending on the elasticity of the composite material of the inner layer of the blade, produced by pretensioning the elements of the inner layer of the blade at the points of fastening to the elements of the load-bearing structures; the profile ends in a fairing or flap, whose curvature increases toward the axis of rotation; vortex cord formers are arranged on the internal concave surface of the compound layer, oriented in the direction of the incoming stream and tapering toward the axis of rotation, while the cross section of the former is saw-shaped with asymmetrical sides, the smaller of which is a concave arc, and the edges of the former are in the shape of an asymptotically decreasing profile.
 3. The stream vortex transformer according to claim 2, further characterized in that the profile of its aerodynamic projection has a narrow-cylindrical shape with a conical tip at one end according to the Phyllotaxis rule.
 4. The stream vortex transformer according to claim 2, further characterized in that the profile of its aerodynamic projection has a spindle shape according to the Phyllotaxis rule.
 5. The stream vortex transformer according to claim 2, further characterized in that the profile of its aerodynamic projection has a conical shape according to the Phyllotaxis rule.
 6. The stream vortex transformer according to claims 2 to 5, further characterized in that the axis of rotation coincides with the direction of the incoming stream.
 7. The stream vortex transformer according to claims 2 to 6, further characterized in that the axis of rotation does not coincide with the direction of the incoming stream.
 8. The stream vortex transformer according to claims 2 to 7, further characterized in that the shape of each individual element of the compound layer has a shape close to the shape of a trapezium.
 9. The stream vortex transformer according to claims 2 to 8, further characterized in that the smaller concave arc-shaped side of the vortex cord former, which is the working side, is oriented to face the flow reflected from the internal surface of the blade, when the axis of rotation of the rotor is placed vertically.
 10. The stream vortex transformer according to claims 2 to 9, further characterized in that the blade holders are arranged on the axis of rotation along a helical line with a variable angular displacement according to the Phyllotaxis rule. 